Given:

V\(_A\) = 20cm\(^3\);  C\(_A\) = 2.0M; C\(_B\) = 0.05M; V\(_B\) = ?

  CH\(_3\)COOH  +  NaOH → CH\(_3\)COONa  +  H\(_2\)O 

 1 mole  : 1 mole

n = \(\frac{CV}{1000}\)

 = \(\frac{{2}\times{20}}{1000}\)

n = 0.04 mole  :  0.04 mole

 But n = \(\frac{mass}{Molar Mass}\)

  m = n x M

  = 0.04 x 82 

 mass  = 3.28g 

Therefore, the mass of the salt is 3.28g

N.B: 82 is the Molar mass of the salt, CH\(_3\)COONa = 12 + (1 x 3) + 12 + 16 + 16 + 23 = 82g/mol